ColorAcademy 2005 - Flight Deck

Colour and the Flight Deck
By Sacha Khamnei, First Officer, Air Southwest

To many the flight deck can appear to be maze of lights switches and gauges. To the trained pilot however, they are the tools that allow him to navigate an aircraft many hundreds and thousands of miles safely, efficiently and quickly. That said however, the pilot’s job would be almost impossible without the concept of flight deck design and its use of colour.

When a pilot is flying an aircraft he is often on his own, at least where small aircraft are concerned. He has to fly the airplane, navigate and communicate with the outside world, all at the same time. Because of this, colour replaces text as the pilot does not have enough time to read messages. He needs to know if there is something wrong with an engine or system but hasn't got time to read a little sign nor would it catch his eye as well as a flashing light.

Instrumentation Examples: The Airspeed Indicator

1. Airspeed Indicator

It has already been noted that the pilot does not have time to read exact speeds and therefore colour coding is an important aspect of the airspeed indicator. The white arc stretching from 70 to 115 knots (nautical miles per hour) indicates the speeds that the flaps on the wings can be deployed in. Exceeding this arc would damage the flaps of the aircraft, sometimes over stressing them to the point of breakage. The green arc signifies the normal operating speeds, if the pilot allows the speed to drop below the green arc then the aircraft will stall (loose all lifting capabilities) and will be overcome by gravity. The yellow arc is the speed at which the pilot cannot perform any strenuous maneuvers as this can damage the

airframe. The red line is the never exceeded speed; the speed that would certainly damage the airframe and seriously compromise the safety of the flight.

Instrumentation Examples: The Attitude Indicator

2. Attitude Indicator

The attitude Indicator shows the aircraft's position relative to the earth's horizon. The upper section painted in light blue represents the sky, and the lower brown section the ground. These colours are very important to the pilot, particularly those involved in aerobatics. It is the only reliable means of orientation with the outside world where the pilot quickly needs to tell if he is upside-down or not. If the aircraft is flying in cloud the pilot can execute a steady turn or simply keep the aircraft straight and level; something he could not do without the simple and intuitive colour references of the earth and sky.

Colour used on Glass Displays

3. A "Glass Cockpit" in a Bombardier CRJ-200

The "glass cockpit" offers easy-to-read graphical views of key flight indicators, replacing the traditional mechanical gauges such as attitude display and mach speed. Cathode-Ray-Tube displays also enable the wide ranging and flexible use of colour, though this freedom should normally be exercised with restraint.Colour is useful in all types of display for categorizing information. Fixed information for example the datum for the engines is in white, thus reducing their visual prominence in comparison to the ‘live’ information on display. The graphical form as mentioned before is very effective. The numbers displayed by the graphical information exist simply to give the pilot an accurate reading of a particular instrument, and are not designed to be referred to "at a glance".

In-flight Alerts and General Psychology of the Flight Deck

As a general rule, flashing red should only be used for information requiring immediate attention. Red and yellow or amber are used for less immediate problems, and white and green for satisfactory or non critical information. In the glass cockpit it is possible for the colour of information to change, indicating a change of state for example, from altitude capture (blue) to altitude hold (green), thus meaning that the colour denotes the nature of the alert, thus saving time and reducing the pilot’s workload.

Such colour changes are highly useful, and flight decks should normally be designed so that the state of a variable is indicated only by colour with no associated change of caption text or location.

Lighting Considerations

Red light should be used with extreme care on the flight deck particularly at night. The reason for this is that text, especially small print becomes unreadable under red light. Therefore red light should be kept to a minimum in the flight deck.

Bibliography

GREEN, R.G et al (2001) Human Factors for Pilots 2nd Edition. Aldershot: Ashgate.
THOM, T (2000) The Aeroplane - Technical. Shrewsbury: Airlife Publishing.

Written by Sacha Khamnei, First Officer, Air Southwest.
Edited by Ben Adamson.